Jeweler&#39;s lathe-chuck.



-No. 861,120. PATENTED JULY 23, 1907.

G. F. HORNBBGK.

JEWELERS LATHE CHUCK;

APPLIGATION.IILED 001210. 1906.

$3 0 0 \CJKIS? O O INVENTOR WITNESSES:

rns mamas PETERS co., wAsmNamN, n. c.

emmam ATTORNEY CORNELIUS F. HORNBEOK, OF CORTLAND, NEW YORK.

JEWELERS LATHE-CHUCK.

Specification of Letters Patent.

Patented July 23, 1907.

Application filed October 10, 1906. Serial No. 338,254.

To all whom it may concern:

, Be it known that I, CORNELIUS F. HORNBECK, a citizen of the United States, residing at Cortland, in the county of Cortland and State of New York, have invented certain new and useful Improvements in Jewelers Lathe-Chucks, of which the following is a specification.

This invention relates to improvements in lathe chucks used by jewelers and watch repairers for holding the balance wheels of watches when inserting and truing up the pivots at the ends of the balance wheel stalf. I

One object of my improvements is to provide a chuck whereby the staff and wheel may be held in position for doing this work without removing therefrom the hair-spring or roller plate.

A further object is to provide means for adjusting the chuck to receive staffs of different lengths and pivots of different diameters, according to the size of the balance wheel to be operated upon. And a final object is to provide means foradjusting the staff when positioned in the chuck so as to bring the pivots at each end into true axial alinement.

I attain these objects by constructing the chuck in the manner illustrated in the accompanying drawings, in which-- Figure 1 represents an end view of the chuck, on an enlarged scale, with a balance wheel in place therein; Fig. 2, a side elevation of the same; Fig. 3, a longitudinal section with the balance wheel removed; Fig. 4, a view of the cross-bar removed, looking at it from the inward side; Fig. bar on the line aa in Fig. 4; Fig. 6, a plan view of the removable bearing plate for the cross-bar; Figs. 7 and 8, details showing another construction of the cross-bar; and Figs. 9 and 10, views on a smaller scale showing a cap adapted to be slipped over the chuck flush with the outer surface of the cross-bar to prevent the tool from passing back of the cross-bar when the chuck is in operation.

Like numerals designate like parts in views.

The chuck consists of a face plate 1 of disk form having a hub 2 at one side, from which projects a screw threaded stud 3 for attaching the chuck to the lathe. This stud may be in the form of a separate piece, as illustrated in Figs. 2 and 3, screw threaded at 4 to pass through the hub 2, the outer end projecting beyond the face plate at 5, where it is provided with a screw threaded socket to receive a centering pin 6, in which is a small hole which tapers from each end of the pin to the center thereof. This pin forms the inner support for the balance wheel staff, and the object of the the several 5, a transverse section of the crossdouble taper is-to prevent the breaking or bending of the pivot where it projects into the hole, should the staff be out of central alinement when inserted in the chuck.

' Near the outer edge of the face plate, at diametrically opposite points, screw threaded posts 7 and 8 are inserted; and, at the rear of the face plate,lock nuts 9 are provided to secure said posts in their adjusted positions. A cross-bar 10 has one end hinged to the outer end of the post 8 by means of a pin 11 which passes through a slotted eye in the knuckle projection 12 formed at this end of the cross-bar, said projection being inserted in a socket provided therefor in the head of the post. At the other end, the cross-bar is notched so as to form the two arms 13, which are adapted to straddle a projection 15 formed on the end of the post 7 and to rest on shoulders l-l at each side of said projection. A screw 16 inserted in said projection and having its head el0ngated to pass over the arms 13 locks the cross-bar to the post, when a balance wheel has been placed in the chuck. A quarter turn of this screw releases the crossbar and permits it to be swung back on the pivot pin in post 8.

In order that the bearing for the balance wheel staff in this cross bar may be brought into exact axial alinement with the bearing in pin 6, I provide means for adjusting the bar longitudinally and transversely. For transverse alinement I provide screws 17 in each of the arms 13, the ends of which screws bear against the sides of the projection 15 on post 7, the opening between the arms 13 being made broader than said projection in order to permit of the necessary side play. By means of these screws 17 the bar may be given a slight movement from one side to the other on post 7 about the post 8 as a center, thereby throwing the bearing at the center of the bar from one side or the other into alinement with the pin 6. For longitudinal alinement, I provide a screw 18 in the head on post '7 which abuts against the projection 19 formed at the end of the crossbar back of the arms 13, and in the head of the post 8 I provide the screw 20 which abuts against the outer end of the knuckle 12 at that end of the cross-bar. By means of these screws it will be evident that the crossbar may be moved longitudinally in either direction, the two adjustments permitting any slight variation from the true axial alinement of the balance wheel staff to be corrected when a balance wheel has been positioned in the chuck.

Since the pivot pins vary in diameter, and the bearing hole in the cross-bar must be of the proper diameter to fit the pivot, in order to properly support it when operating upon it with a working tool, I have shown, in Figs. 3 to 6, a removable bearing plate at 22 at the center of which is a tapered hole surrounded at the outer side by a hub 21 adapted to pass through a corresponding hole in the cross-bar. This plate 22 is of elliptical shape, in order that it may be inserted in a pocket 24 formed on the inside of the cross-bar and, by a quarter turn, made to engage side grooves 23 formed along the outer ,edges of said pocket. By providing the chuck with a number of these plates with different sized holes, the chuck may be made to receive all sizes of balance wheel staffs and their pivot pins.

Where the balance wheel staff is short and the roller plate is near the end of the staff, the roller jewel will project to such an extent as to bear against the crossbar. I, therefore, provide at 25 a slot into which the roller jewel may pass in such a case.

To accommodate the chuck to different lengths of staffs, the cross-bar must be set at the proper distance from the center pin 6, and I have shown two means for accomplishing this adjustment. By unscrewing the stud 3 in the hub 2, the end 5 may be retracted, carrying with it the center pin 6, and when at the proper distance from the cross-bar the hub may be secured to the stud in the adjusted position by means of set screw 30 shown in Fig. 2. A larger adjustment, however, may be attained by means of the screw threaded posts 7 and 8, which may be given the required number of turns in or out from the plate 1 and locked in position by means of the lock nuts 9. Either or both of these adjustments may be provided, or I may rely entirely "upon the adjustment of the posts 7 and 8, making the stud 3 and hub 2 in one piece. By screw threading the pin 6 into the projection 5, said pin may be renewed from time to time or pins having different bores may be inserted and properly adjusted in said projection.

To hold the balance wheel from turning in the chuck, I provide a series of socket holes at 26 in the face plate to receive pins which will project from the face plate in position to engage the balance wheel, as shown in Fig. 1. Since the pivot pins are short, especially in the smaller sizes of watches, it will be evident that the crossbar 10 at the center, where the bearing hole for the pivot is located, must be very thin and plates 22 must be made correspondingly. For this reason I have shown, in Figs. 7 and 8, another form of the cross-bar, which will be perhaps preferable to that already described. In this form, the crossbar 31 is made from a thin plate separate from the end pieces 34 and 35, which carry the side arms13 and the knuckle 12, respectively, the plate 31 being secured to the end pieces 34 and 35 by means of screws 36. At 32 the plate is provided with a hole of a diameter to receive a given staff pivot, and there will be as many plates as there are different diameters of pivots, the plates being changed on the end pieces 34 and 35 according to the requirements of any given balance wheel. At 33 the crossbar is provided with a slot to receive the roller jewel;

In Figs. 9 and 10 I have shown a cross-section and inside view of a cap adapted to be slipped on the chuck to prevent the tools from passing inside of the cross-bar when operating upon the pivot. This cap 27 is provided with a diametrical slot 28, into which the cross bar fits, when the cap is slipped upon the face plate 1, the peripheral wall of the cap being pressed out at opposite sides, as shown at 29 to permit it topass by the screws 18 and 20. The face plate may be made, how- Having thus described my improved chuck, what I claim as my invention and desire tosecure by Letters-- Patent is:

1. A balance wheel chuck, comprising a face-plate provided at the center with a socket to receive one end of a balance wheel staff, means for attaching the face plate to a lathe spindle, posts projecting 'from the face-plate at diametrically opposite sides of the socket, and a cross-bar having a hinged connection with one of the posts and an interlocking connection with the other post, said crossbar being provided with a socket to receive the other end of the staff, and said socket having an aperture at its outer end through which the staff pivot will project.

2. A balance wheel chuck, comprising a face-plate provided at the center with a socket to receive one end of a balance wheel staff, means for attaching the face-plate to a lathe spindle, posts projecting from the face plate at diametrically opposite sides of the socket, and a cross-bar transversely adjustable with respect to the axis of the chuck carried by the posts and provided with a socket to receive the other end of the staff, said socket having an aperture at its outer end through which the staff pivot will project.

A balance wheel chuck, comprising a face-plate provided at the center with a socket to receive one end of a balance wheel staff, means for attaching the faceplate to alathe spindle, posts projecting from the face-plate at diametrically opposite sides of the socket, across-bar carried by the posts, and a change-plate removably fastened to the cross-bar and provided with a socket to receive the other end of the staff, said socket having an aperture at its outer end through which the staff pivot will project.

4. A balance wheel chuck, comprising a face-plate provided at the center with a socket to receive one end of a balance wheel staff, means for attaching the face-plate to a lathe spindle, posts projecting from the faceplate at diametrically opposite sides of the socket, a cross-bar hinged at one end to the outer end of one of said posts and having its other end bifurcated to engage a shouldered projection at the outer endof the other post, means for locking said end to said projection, said crossbar being provided with a socket to receive the other end of the staff and said socket having an aperture at its outer end through which the staff pivot will project.

5. A balance wheel chuck, comprising a face-plate provided at the center with a socket to receive one end of a balance wheel staff, means for attaching the face-plate to a lathe spindle, posts projecting from the face-plate at diametrically opposite sides of the socket, a cross-bar hinged at one end to the outer end of one of said posts and having its other end bifurcated to engage a shouldered projection at the outer end of the other post, means for locking said end to said projection, said crossbar being pro vided with a socket to receive the other end of the staff and said socket having an aperture at its outer end through which the staff pivot will project, set screws on the two posts adapted to adjust the cross-bar longitudinally in either direction, the hinge knuckle on the crossbar being slotted to permit of such movement, and set screws on the bifurcations of the cross-bar bearing against the post projection at that end to adjust the bar transversely.

G. A balance wheel chuck, comprising a face-plate, pro vided at the center with a socket to receive one end of a balance wheel staff, means for attaching the face-plate to a lathe spindle, posts projecting from the face-plate at diametrically opposite sides of the socket, a cross-bar carried by the posts and provided with a socket to receive the other end of the staff, said socket having an aperture at its outer end through which the staff pivot will project, and means for adjusting said posts in the faceplate to set the crossbar at different distances therefrom to accommodate the chuck to different lengths of staffs.

7. A balance wheel chuck, comprising a face-plate provided at the center with a socket to receive one end of a balance wheel staff, means for attaching the face-plate to a lathe spindle, posts projecting from the face-plate at diametrically opposite sides of the socket, a cross-bar car- 1 posts and an interlocking connection with the other of the 10 ried by the posts and provided with a socket to receive the posts.

other end of the staif, said socket having an aperture at In testimony whereof I have aflixed my signature, in

its outer end through which the staff pivot will project, presence of two witnesses.

and a slotted cap adapted to he slipped over the chuck 7 with its outer face flush with the cross-bar. CORNELIUS HORNBECK 8. In a chuck of the character described, the combina- Witnesses:

tion, with a face plate and posts projecting therefrom, of H. J. HARRINGTON,

a cross-bar having a hinged connection with one of the S. K. JONEs. 

